# coding:utf-8

from ctypes import *

import win32gui

# 查找窗口
hwnd = win32gui.FindWindow(None, "请求内容中...")
# 发送消息，交给pb处理
if (windll.user32.IsWindow(hwnd)):
    windll.user32.SendMessageW(hwnd, 1600, 0, "我是标题")
    print('111')
